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Indonesia: Sensor in the sky

11 June 1994

By Brett Wright and Peter Quiddington

A POWERFUL remote sensing system, currently under development in Australia and Indonesia, promises to rival the use of satellite data for environmental surveying and management. But one of the first planned uses of the technology could be controversial – a survey of the remote Mamberamo Valley in north- western Irian Jaya where a hydroelectric scheme and industrial complex has been proposed (see Box 1).

The system, known as the Australian Asian Visible Imaging Spectrometer (AAVIS), is essentially an electronic eye or scanner which can capture digital images of the Earth’s surface in fine detail. It is able to analyse an area of land or sea as small as 12 square metres, compared with a minimum of 100 to 900 square metres for satellites.

The electronic eye – which is mounted on an aircraft – can distinguish 40 to 70 times the number of individual colours in an image than can be achieved by instruments carried on satellites, according to Steven Chadd from the Melbourne engineering firm, Trippett Shedden. This capability will allow users, for example, to distinguish easily between toxic blue-green algae and benign green algae within a single lake or river.

“Our goal is to reach a level of spatial and spectral resolution which will indicate the health of whatever is being looked at,” Chadd said.

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The power of the instrument is due in large part to scientific algorithms developed by Australia’s chief research agency, the CSIRO, in collaboration with Trippett Shedden, and the Australian Institute of Marine Science in Townsville. Indonesia, which is seeking to boost its expertise in advanced electronics for the aviation industry, is collaborating in the development of a commercial product which can be marketed throughout the Asia-Pacific region (see Box 2).

Research over the past decade, principally by CSIRO’s Institute of Natural Resources and Environment, has culminated in the development of image- processing software which can extract detailed information from an image such as the condition of plants and other organisms growing in a paddock, or even on the bottom of a lake.

Organisms reflect light in a particular way. This characteristic, called a spectral signature, allows them to be identified. In visible light, these signatures would be called colours or fine shades of colour, but they also include parts of the infrared spectrum invisible to the human eye. CSIRO’s understanding of the spectral signatures, combined with the physics of how reflected light travels through and is absorbed by water, allows scientists to see into a body of water from the air, and determine the presence or absence of particular organisms at a depth of up to 15 metres.

Using a prototype of the AAVIS system, Trippett Shedden recently surveyed Melbourne’s Port Phillip Bay to map areas where scallops may live and regions containing seagrass mats, which provide a home for many species of commercial fish.

“From the air, in a period of about five days, we surveyed the entire bottom of the bay except for the deep channels,” said Chadd, who is Trippett Shedden’s project manager for AAVIS. “We can tell you that the water is the colour it is due to a particular organism living on the bottom.”

The prototype system uses a scanner built by a Canadian company, Itris Research. The scanner is able to distinguish 288 spectral bands or “colours” of light in the visible and near-infrared electromagnetic spectrum. A more powerful instrument is likely to be built in Australia, and will be able to distinguish 512 spectral bands. By comparison, the widely-used Landsat satellite imagery contains only 7 spectral bands.

Chadd claims AAVIS has three main advantages over satellites&colon; more spectral data is possible, it can be used when and where needed, and the data produced is owned by those using the system, whereas satellite is available to anyone willing to pay.

AAVIS also promises quicker results than surveys done on the ground or by boat. A survey of algae in Sydney’s Hawkesbury River was completed by Trippett Shedden in three days – a task that would normally take divers months or even years to complete to the same level of accuracy.

The company plans to offer a commercial remote sensing service internationally within the next two years. The service will provide information such as whether a coral reef is living or dead, whether a wheat crop is healthy or stressed by drought, or whether a grassland is becoming environmentally degraded.

AAVIS is one of a number of aerospace technologies, including a network of ground stations for satellites and a service to predict changes in the ionosphere, which are being considered for possible joint development between Australia and Indonesia as part of an agreement known as COSTAI (see page 5).

Box 1

A SIGN that the Indonesians were particularly interested in AAVIS came last month when Trippett Shedden, an engineering firm in Melbourne, was invited by Indonesia’s Agency for that Assessment and Application of Technology (BPPT) to take part in the initial planning of a scheme combining industry, agriculture and hydroelectricity generation in the remote Mamberamo Valley in northwestern Irian Jaya.

But the scheme could run into problems. In the past, conservation groups have claimed such schemes were not suitable for tropical regions. The creation of large bodies of water in warm regions can cause the sudden influx of new species, particularly birds and insects. These can have a detrimental effect on indigenous species and may introduce disease.

Indonesian officials are likely to argue that, by using AAVIS, the scheme can be designed and managed in an environmentally sensitive way.

But Australia is giving tacit endorsement to the scheme by assisting with the introduction of AAVIS. “If Indonesia is going to get into a massive development project, then it would be sensible for them to do some surveying and that is where we can help,” says David McEwan, of the Department of Industry, Science and Technology’s International Collaboration Branch. In its commercial dealings with Indonesia, Australia is not in a position to make a moral judgment on the way the country develops, he said. “We can help to repair the effects of rapid development that has occurred and help plan development to avoid problems in the future.”

Box 2

LATE LAST year the deputy chairman of Indonesia’s Bureau of Industry Strategy, Dr Wisnubroto, said&colon; “Indonesia has an aerospace industry but no infrastructure. Australia has an infrastructure to support a global aerospace industry. So the two should be able to cooperate for mutual benefit.”

It is this thinking which lies behind the joint venture to develop a high resolution imaging technology.

Over the past 18 years Indonesia has poured about A&dollar;1.5 billion into the creation of an aviation industry. But it is struggling to compete on the world market because of a lack of support industries, such as advanced electronics, and a dearth of skilled workers.

Just across the Timor Sea, Australia performs world class research and development and has well established training facilities. But it only has a small manufacturing base and a limited local market.

Bucharuddin Jusuf Habibie, Indonesia’s Minister for Research and Technology and the driving force behind the aviation industry, wants Indonesia to be a collaborator in high technology ventures, not just a consumer. The AAVIS project is appealing to Indonesia because it could lead to a commercial system that could fly on an Indonesian aircraft. The aim will be to market a service based on AIVIS throughout the region.